Glycosylated and Succinylated Macrocyclic Lactones with Amyloid-β-Aggregation-Regulating Activity from a Marine Bacillus sp

Two new glycosylated and succinylated macrocyclic lactones, succinyl glyco-oxydifficidin ( ) and succinyl macrolactin O ( ), were isolated from a strain collected from an intertidal mudflat on Anmyeon Island in Korea. The planar structures of and were proposed using mass spectrometric analysis and NMR spectroscopic data. The absolute configurations of and were determined by optical rotation, -based configuration analysis, chemical derivatizations, including the modified Mosher's method, and quantum-mechanics-based calculation. Biological evaluation of and revealed that succinyl glyco-oxydifficidin ( ) inhibited/dissociated amyloid β (Aβ) aggregation, whereas succinyl macrolactin O ( ) inhibited Aβ aggregation, indicating their therapeutic potential for disassembling and removing Aβ aggregation.